An issue of an engine oil consumption in an engine causes more attention in the design of an engine assembly in automotive industries. Reduction on the engine oil consumption may be achieved by improvement on a positive crankcase ventilation (PCV) system. With a high-performance oil separator, a high capacity oil drain tube in the PCV system is required.
An oil drain tube is usually an individual tube disposed in the oil pan of the PCV system. However, the individual oil drain tube in the oil pan has some issues, such as difficulty on package and the NVH problem caused by the oil drain tube. In some oil pans, an oil drain tube is replaced by a check valve. However, the use of the check valve increases a manufacturing cost, and the oil residue in the oil pan may wear the check valve and thus affect its normal operation.